Tetramolopium filiforme, a short- lived perennial member of the aster family (Asteraceae), is a dwarf shrub from 5 to 15 cm (2 to 6 in) tall with complexly branched stems. Leaves are much longer than wide, 1 to 2 cm from (0.4 to 0.8 in) long and 0.4 to 1.2 mm (0.02 to 0.05 in) wide. Flower heads are single or grouped in clusters of 2 to 4, each having a bell-shaped involucre 4 to 5 mm (0.2 in) high and 7 to 10 mm (0.3 to 0.4 in) in diameter. There are 35 to 52 white or pale lavender petals (ray florets) in a single circle at the edge of the head, each 3 to 4 mm (0.1 to 0.2 in) long. There are 18 to 30 maroon (rarely yellow) disk florets in the center of each head. The ray florets are female, while the disk florets function as male flowers. Fruits are achenes, less than 3 mm (0.1 in) long and up to 1 mm (0.04 in) wide. This species is distinguished from the other extant species on Oahu by its separate male and female flowers both on the same plant, and its inflorescence of one to four heads. Two different varieties of this species are recognized. Tetramolopium filiforme var. filiforme has linear-filiform leaves with entire margin and T. filiforme var. polyphyllum has linear-oblanceolate leaves with coarsely dentate margins.